Surgical instrument and method of use for inserting an implant between two bones

ABSTRACT

The surgical instrument includes a handle assembly and an elongate body that has first and second ends with the first end being located adjacent to the handle assembly and the second end being moveably connected to an implant engagement assembly. The surgical instrument also has a length control mechanism that includes a gripping portion, a drive shaft and a gear assembly. The surgical instrument further has a locking mechanism that includes a gripping portion, a connecting rod and a coupling end. The length control mechanism functions to adjust the overall length of an implant that is held by the implant engagement assembly before being implanted in vivo. The locking mechanism operates to secure the overall length of the implant following final length adjustment and implantation. A surgical method for using the surgical instrument, a method of fabrication and a spinal implant insertion kit is also disclosed.

TECHNICAL FIELD

The present invention relates generally to orthopedic and neurosurgicalinstrumentation and techniques, and more specifically, but notexclusively, concerns an inserter to be used to implant a device betweentwo bones.

BACKGROUND OF THE INVENTION

Damage or disease that affects the integral structure of a bonestructure or more specifically, a vertebral body within an individual'sspinal column may lead to neurologic impairment with possible permanentdamage to the surrounding tissue. Maintaining proper anatomic spacingwithin a bone structure and the spinal column is critical to ensuringcontinued functionality of the surrounding tissue and for the spinalcolumn, the spinal cord and nerve roots and therefore, avoidance of longterm serious neurological impairment.

Typically, spinal implants that are used as a spacer type of device havea fixed overall length and are implanted without the ability to adjustthe degree of expansion or curvature without using multiple insertioninstrumentation. A need remains for a multipurpose instrument to be usedto implant a spacer type of implant that allows the surgeon to minimizethe size of the surgical incision, facilitate the operative techniqueand decrease patient morbidity.

SUMMARY OF THE INVENTION

Advancement of the state of the surgical instrumentation that are usedto implant devices between two bones and more specifically, spinalimplants for use in the surgical management of patients with missing ordamaged vertebral bodies within an intact spinal column is believeddesirable. The present invention satisfies the need for improvements tosurgical instruments used to insert and adjust bone spacer devices andimplants, but more specifically, vertebral spacer devices that areimplanted in patients suffering from either diseased or damagedvertebral bodies by providing a multi-functional instrument that allowsthe operating surgeon to grasp, change the length and secure a variablelength vertebral body replacement device following insertion into thewound site and spinal column.

The present invention provides in one aspect, a surgical instrument forinserting an implant between two bones that includes a handle and anelongate member that has a first end and a second end, and alongitudinal axis extending between these two ends with the second endbeing moveably connected to an implant engagement assembly that ispositioned at a distal end of the surgical instrument. The implantengagement assembly is configured to hold the implant. Movement of theelongate member relative to the implant engagement assembly results inthe implant engagement assembly adjusting the implant to allow theoperating surgeon to place the implant between the two bones.

The present invention provides in another aspect, a surgical instrumentfor inserting a spinal implant between two vertebrae that includes ahandle assembly at the proximal end of the surgical instrument and anelongate member that has a first end and a second end with alongitudinal axis extending between the two ends. The first end islocated adjacent to the handle assembly and the second end is configuredto be rotationably connected to the spinal implant engagement assemblythat is positioned at the distal end of the surgical instrument. Thesurgical instrument also includes a length control mechanism foradjusting the overall length of the spinal implant when the spinalimplant has been placed between two vertebrae. The length controlmechanism is constructed with a gripping portion, a gear assembly and adrive shaft that is positioned intermediate the gripping portion andgear assembly. The drive shaft extends through a first opening withinthe handle assembly and is oriented substantially parallel to thelongitudinal axis of the elongate member. The surgical instrumentfurther includes a first locking mechanism for securing the overalllength of the spinal implant after the spinal implant has been placedbetween the two vertebrae. The first locking mechanism has a grippingportion proximate to the proximal end of the surgical instrument, acoupling end and a connecting rod that is intermediate the grippingportion and the coupling end. The connecting rod extends through asecond opening in the handle assembly and is oriented substantiallyparallel to the longitudinal axis of the elongate member.

The present invention provides in yet another aspect, a surgical methodfor inserting an implant between two bones that includes the step ofsurgically creating an opening on the skin of a patient that isproximate the location of the two bones. The method further includes thestep of obtaining a surgical instrument that has a handle assembly, anelongate member that has a first end and a second end, and alongitudinal axis that extends between the two ends. The first end ispositioned adjacent to the handle assembly and the second end is beingmoveably connected to the implant engagement assembly that is located atthe distal end of the surgical instrument. The surgical instrument alsohas a length control mechanism for adjusting the overall length of theimplant when the implant has been placed between the two bones with thelength control mechanism having a gripping portion, a gear assembly anda drive shaft that is intermediate the gripping portion and gearassembly. The drive shaft is configured to extend through a firstopening within the handle assembly and is oriented substantiallyparallel to the longitudinal axis of the elongate member. The surgicalinstrument further includes at least one locking mechanism for securingthe overall length of the implant after the implant has been placedbetween the two bones. The at least one locking mechanism has a grippingportion proximate to the proximal end of the surgical instrument, acoupling end and a connecting rod that is intermediate the grippingportion and the coupling end. The connecting rod extends through asecond opening in the handle assembly and is oriented substantiallyparallel to the longitudinal axis of the elongate member. The surgicalmethod usually includes the further steps of coupling the implant to theimplant engagement assembly and then inserting the surgical instrumentand coupled implant into the skin opening. The surgical method mayfurther include the step of positioning the implant into the spacebetween the two bones. Yet a further step of the method may be to extendthe implant to an overall length that causes the implant to contact andapply a force to the two bones to maintain the space between the twobones. The surgical method typically includes another step of fixing orsecuring the overall length of the inserted implant.

The present invention provides in another aspect a method of fabricatinga surgical instrument. The method may include the step of providing ahandle assembly. The method of fabrication may include the further stepof providing an elongate member that has a first end and a second endwith a longitudinal axis extending between the two ends. The first endis positioned adjacent to the handle assembly and the second end ismoveably connected to the implant engagement assembly that is located atthe distal end of the surgical instrument. Movement of the elongatemember relative to the handle assembly and the implant engagementassembly results in the implant engagement assembly being coupled to theimplant to allow for placement of the implant between the two bones.

Yet a further aspect of the present invention provides a spinal implantinsertion kit that includes a spinal implant that is to be placedbetween two vertebrae and a surgical instrument that has a handleassembly and an elongate member that has a first end and a second endwith a longitudinal axis extending between the two ends. The first endis positioned adjacent to the handle assembly and the second end ismoveably connected to the spinal implant engagement assembly that is atthe distal end of the surgical instrument. The surgical instrument alsohas a length control mechanism for adjusting the overall length of thespinal implant when the spinal implant has been placed between the twovertebrae. The length control mechanism has a gripping portion, a gearassembly and a drive shaft positioned intermediate the gripping portionand gear assembly with the drive shaft extending through a first openingwithin the handle assembly. The device shaft is also orientedsubstantially parallel to the longitudinal axis of the elongate member.The surgical instrument also includes at least one locking mechanism forsecuring the overall length of the spinal implant after the spinalimplant has been placed between the two bones. The at least one lockingmechanism has a gripping portion proximate to the proximal end of thesurgical instrument, a coupling end and a connecting rod that isintermediate the gripping portion and the coupling end. The connectingrod extends through a second opening in the handle assembly and isoriented substantially parallel to the longitudinal axis of the elongatemember.

Further, additional features and advantages are realized through thetechniques of the present invention. Other embodiments and aspects ofthe invention are described in detail herein and are considered a partof the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features andadvantages of the invention are apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a perspective view of one embodiment of a surgical instrument,in accordance with an aspect of the present invention;

FIG. 2 is an enlarged, exploded perspective view of a distal end of thesurgical instrument of FIG. 1 showing the distal aspects of an elongatemember and a locking mechanism with an implant engagement assembly thatincludes an actuation body, a holding portion and an alignment body, inaccordance with an aspect of the present invention;

FIG. 3 is a side elevational view of the surgical instrument of FIG. 1,in accordance with an aspect of the present invention;

FIG. 4 is a top view of the surgical instrument of FIG. 1, in accordancewith an aspect of the present invention;

FIG. 5 is an enlarged, side elevational view of the assembled distal endof the surgical instrument of FIG. 1 showing the elongate member withexternal threads, the locking mechanism with a bearing portion, theimplant engagement assembly, including the actuation body and holdingportion with engagement member and the alignment body, in accordancewith an aspect of the present invention;

FIG. 6 is an enlarged, top view of the assembled distal end of thesurgical instrument of FIG. 1 showing the elongate member with externalthreads, the locking mechanism with a coupling end, the implantengagement assembly, including the actuation body and the holdingportion that includes the first and second arms and correspondingengagement members and the alignment body. Also seen, is the distal endof a length control mechanism, including a gear assembly, in accordancewith an aspect of the present invention;

FIG. 7 is an enlarged, perspective view of the assembled distal end ofthe surgical instrument of FIG. 1 showing the elongate member, thelocking mechanism with the bearing portion, the implant engagementassembly including the actuation body and the holding portion thatincludes the first and second arms with the corresponding engagementmembers and the alignment body. Also seen, is the distal end of thelength control mechanism with the gear assembly, in accordance with anaspect of the present invention;

FIG. 8 a cross-sectional, perspective view of the surgical instrument ofFIG. 1 taken along line 8-8, showing a top portion of the handleassembly, the elongate member and the implant engagement assembly, thelength control mechanism and the locking mechanism, in accordance withan aspect of the present invention;

FIG. 9 is a perspective view of a spinal implant coupled to the surgicalinstrument of FIG. 1, shown positioned prior to insertion into a spacebetween two vertebral bodies, in accordance with an aspect of thepresent invention;

FIG. 10 is a perspective view of the spinal implant coupled to thesurgical instrument of FIG. 1, shown positioned in a space between twovertebral bodies with the length control mechanism being rotated toextend the spinal implant to allow the ends to make contact with thesuperior and inferior vertebral bodies to maintain a desired spacingarrangement within a spinal column, in accordance with an aspect of thepresent invention;

FIG. 11 is an enlarged top view of distal end of the surgical instrumentof FIG. 1, showing the gear assembly inserted into the spinal implant,in accordance with an aspect of the present invention;

FIG. 12 is a perspective view of the spinal implant coupled to thesurgical instrument of FIG. 1, shown positioned in a space between twovertebral bodies following final length determination with the lockingmechanism being rotated, in accordance with an aspect of the presentinvention; and

FIG. 13 is an enlarged top view of the distal end of the surgicalinstrument of FIG. 1, showing the coupling end and attached lockingpin/screw being inserted into the spinal implant, in accordance with anaspect of the present invention.

DETAILED DESCRIPTION FOR CARRYING OUT THE INVENTION

Generally stated, disclosed herein is a surgical instrument for use ininserting an implant into a space between two bones. More specifically,the surgical instrument will typically be used to hold, extend/contractand lock a vertebral body replacement implant during implantation intothe spinal column. The surgical instrument generally includes a handleassembly, an elongate member that includes an implant engagementassembly at the distal end. The implant engagement assembly furtherincludes an actuation body and an implant holding portion that has twoarms that move and grasp the implant when the actuation body isactuated. The surgical instrument further includes a length controlmechanism and locking mechanism. The distal end or gear assembly of thelength control mechanism is inserted into the implant and couples to acorresponding length adjustment mechanism to allow for varying theoverall length of the implant. The surgical instrument typically furtherincludes a locking mechanism that provides for the insertion of alocking pin or screw into the implant to fix the overall length of theimplant.

As used herein, the terms “surgical instrument” and “inserter” may beused interchangeably as they essentially describe the same type ofoperative instrument. Further, described herein is a surgical method forusing the surgical instrument, a method of fabricating the surgicalinstrument and a spinal implant insertion kit that is used to maintain aspace between two vertebrae within a patient suffering from a diseasedor damaged spinal column.

As depicted in FIGS. 1, 3 and 4, the general arrangement of a surgicalinstrument 10, in accordance with an aspect of the present invention,includes a handle assembly 100, an elongate member 201, an implantengagement assembly 204, a length control mechanism 300, and at leastone locking mechanism 400. Surgical instrument 10 is to be used tograsp, expand and contract the length and secure the overall length ofthe implant when placed within the body. One type of implant that may beused with surgical instrument 10 is the one described in co-pending U.S.patent application Ser. Nos. 11/928,532 and 11/928,553. The contents anddisclosure provided in these two pending U.S. applications are herebyincorporated herein by reference.

In this detailed description and the following claims, the wordsproximal, distal, anterior, posterior, medial, lateral, superior andinferior are defined by their standard usage for indicating a particularpart of a bone, prosthesis or surgical instrument according to therelative disposition of the surgical instrument or directional terms ofreference. For example, “proximal” means the portion of an instrumentpositioned nearest the torso, while “distal” indicates the part of theinstrument farthest from the torso. As for directional terms, “anterior”is a direction towards the front side of the body, “posterior” means adirection towards the back side of the body, “medial” means towards themidline of the body, “lateral” is a direction towards the sides or awayfrom the midline of the body, “superior” means a direction above and“inferior” means a direction below another object or structure.

With reference to FIGS. 1 and 3, surgical instrument 10 includes handleassembly 100, elongate member 201, implant engagement assembly 204 thatfurther includes an actuation body 205, an alignment body 214 and aholding portion 206. Further included in surgical instrument 10 islength control mechanism 300 and at least one locking mechanism 400 thatis oriented to run parallel to a longitudinal axis 210 of elongatemember 201.

As shown in FIG. 1, handle assembly 100 of surgical instrument 10 alsoincludes a body portion 101 and a top portion 102. Body portion 101 isgenerally configured as a grip or holder to accommodate the palm andfingers of the operating surgeon. It is contemplated that body portion101 may be available in varying sizes and configurations to allow forsurgical instrument 10 to be used in a wide range of surgicalapplications, including endoscopic procedures and approaches as well asfit various user hand sizes without sacrificing dexterity and comfort.Centered in top portion and extending in proximal to distal direction isat least one through hole 103. Hole 103 is sized to receive and fix adistal projecting cannulated tube 304 (see FIG. 8) that houses a driveshaft 303 that is a component of length control mechanism 300.

As seen in FIGS. 1 and 8, positioned on either side of hole 103 are twosubstantially parallel through holes 104 that are sized to receive theconnecting rods 403 for the at last one locking mechanism 400. Theembodiment shown for example purposes in FIG. 8, depicts twosubstantially parallel holes 104 that are sized to receive connectingrod 403 of locking mechanism 400. Holes 104 are configured to allowrotary motion of connecting rod 403 when an operating surgeon is usingsurgical instrument 10 to secure the overall length of an implant.

Positioned intermediate handle assembly 100 and actuation body 205 iselongate member 201. FIGS. 1, 3 and 4 show elongate body 201 extendingin a proximal to distal direction with a first end 202 being locatedadjacent to handle assembly 100 and a second end 203 being moveably orrotatably connected to distally positioned implant engagement assembly204 or more specifically, to actuation body 205. As seen in FIGS. 1, 2,3 and 4, elongate member 201 is tube-like in structure with a roundcross-sectional shape, although it is further contemplated that variousgeometric shaped cross-sections may be used in constructing elongatemember 201, including, but not limited to oval, square, square,rectangular and other polygonal shapes. Further, as shown in FIG. 8,elongate member 201 is hollow with the inner diameter being sized toaccommodate and surround cannulated tube 304. First end 202 is generallyshaped as a gripping portion 211 with the configuration providing theoperating surgeon with increased surface area and texture to grip andturn elongate member 201 when necessary. Second end 203 is typicallyconfigured to include a set of external threads 212 that willthreadingly engage actuation body 205. When the operating surgeonrotates elongate member 201, the engaged actuation body 205 movesdistally resulting in holding portion 206 engaging and grasping theimplant. If the operating surgeon were to reverse the direction ofrotation of elongate member 201, this would result in engaged actuationbody 205 moving proximally relative to elongate member 201 and causeholding portion 206 to expand and release the implant from between firstand second arms 207, 208.

FIG. 2 is an exploded view that shows implant engaging assembly 204 inmore detail, specifically actuation body 205 and holding portion 206.Actuation body 205 may further be constructed to include a throughcentral hole 220 with internal threads 209 that engage external threads212. At least two through holes 215 are laterally positioned and may besized to receive connecting rods 403. A slotted transverse opening 221that is sized to slidingly engage the alignment body 214 is positionedin the distal aspect of actuation body 205. Connecting holes 222 forcoupling the drive links 213 may also be constructed in the superior andinferior surfaces of the distal aspect of actuation body 205. A throughhole 223 is positioned along the midline of alignment body 214 and it issized to receive cannulated tube 304 and drive shaft 303. In addition,alignment body 214 may include fixation holes 224 that allow for themoveably coupling of arms 207, 208.

Holding portion 206 as seen in FIGS. 5, 6 and 7 generally includesalignment body 214, drive links 213, first arm 207 and second arm 208with attached engagement members 216 positioned at the distal aspect ofthe first and second arms 207, 207. Holding portion 206 is constructedto allow for first and second arms 207, 208 to move in a directiontowards the midline of surgical instrument 10 and then away from themidline when drive links 213 are moved either distally or proximally,respectively.

As seen in FIG. 6, drive links 213 are attached to actuation body 205,therefore as discussed above, when elongate member 201 is threaded intoactuation body 205 and move actuation body 205 in either a distal orproximal direction, the distally attached drive links 213 will thencause first and second arms 207, 208 to move either towards the midlineor away from the midline. First and second arms 207, 208 are generallyconfigured as L-shaped bodies to facilitate continuous movement whencoupled to drive links 213.

FIGS. 2 and 6 also depict the two engagement members 216 that arepositioned at the distal ends of first and second arms 207, 208.Engagement members 216 are attached to the distal ends of first andsecond arms 207, 208 in a manner that allows engagement members 216 topivot and rotate around the arm ends. This pivoting motion coupled withthe movability of arms 207, 208 allows surgical instrument 10 toaccommodate a broad range of sizes of implants including implants withvariable widths or diameters. Engagement members 216 have a distalsurface 217 that includes an attached engagement element 218 that issized to engage or mate with a corresponding opening on the exteriorsurface of the implant.

As seen in FIGS. 2 and 6, for example purposes, engagement element 218is configured as a knob-like structure, although it is contemplated thatother protrusion-like structures including, but not limited to springballs, rods or pins may be used.

FIGS. 1 and 4 further show length control mechanism 300 that functionsto engage with the implant and mechanically change the overall length ofthe implant both through extension of the implant and contraction orshortening of the implant. This is generally accomplished by using therotary motion of length control mechanism 300 that mates with acorresponding length adjustment mechanism in the implant. The lengthadjustment mechanism of the implant is designed to convert the rotarymotion of the length control mechanism 300 to translational motion,wherein the overall linear length of the implant is then changed. Lengthcontrol mechanism 300 includes a gripping portion 301 that is positionedat the proximal end of surgical instrument 10. Gripping portion 301 istypically shaped as a knob or other similar structure to allow theoperating surgeon easy manipulation. Gripping portion 301 is connectedto the proximal end of drive shaft 303 that extends generally in aproximal to distal direction and is also substantially parallel tolongitudinal axis 210.

As seen in FIG. 8, drive shaft 303 passes through hole 103 and isencased by cannulated tube 304 within handle assembly 100. Cannulatedtube 304 is sized to allow drive shaft 303 to move in a distal toproximal direction and rotate. Attached to the distal end of drive shaft303 is a gear assembly 302.

FIGS. 2, 4 and 6 show gear assembly 302 extending to a distance that isgenerally between arms 207, 208 that enables gear assembly 302 to enterthrough one of the several holes of the implant to engage the lengthadjustment mechanism of the implant. As seen in FIG. 2, gear assembly302 is secured to the distal end of drive shaft 303 approximatelyproximate to the exit point of drive shaft 303 from cannulated tube 304.Because of the securement of gear assembly 302 directly to drive shaft303, when gripping portion 301 is rotated clockwise, this directionalmotion is directly translated to gear assembly 302 that correspondinglyrotates in a clockwise direction. It should be noted that length controlmechanism 300 may be rotated both in a clockwise and counter-clockwisedirection depending on whether the surgeon is lengthening (expanding) orshortening (contracting) the implant.

FIGS. 1, 4 and 8 generally exhibit locking mechanism 400. For examplepurposes, surgical instrument 10 as depicted in these figures includestwo locking mechanisms 400, although it is contemplated that only onelocking mechanism may be necessary for securing the overall length ofthe implant post-implantation. As seen in the cross-section view of FIG.8, locking mechanism 400 has a gripping portion 401 that is positionednear the proximal end of surgical instrument 10 and proximate to handleassembly 100. Gripping portion 401 is typically configured as a knob orother handle-like shape to allow the operating surgeon easy grasping andmanipulation when in use. Connected to gripping portion 401 isconnecting rod 403 that extends in a proximal to distal direction andsubstantially parallel to longitudinal axis 210. Connecting rod 401passes through hole 104 in handle assembly 100, with hole 104 beingsized to allow for rotational and translational movement of connectingrod 403 without any impingement. Connected to the distal portion ofconnecting rod 403 is coupling end 402. (See FIG. 2.)

As seen in FIGS. 2, 5 and 7, connecting rod 403 may include transitionportion 408 that may be slightly curved and fabricated from a flexiblematerial to allow for curving of coupling end 402 and entry intoalignment body 214. Examples of possible flexible materials to use toconstruct transition portion 408 include nitinol or otherelastic/psuedoelastic metals and various compliant polymers, includingbut not limited to polyethylene and polystyrene. Coupling end 402further includes a distal tip 406 that is configured to allow fordetachably coupling of the locking pin/screw following securement withinthe implant. As seen in FIG. 6, distal tip 406 may be shaped as a hex orother geometric shape that would in turn match up with the head of thecorresponding locking pin/screw.

FIGS. 2, 5 and 6 show further that connecting rod 403 may also include abearing portion 407 that slidingly engages with a slot 219 that ispositioned in the lateral side of alignment body 214. Slot 219 isgenerally sized to allow for rotational and translational movement ofbearing portion 407 while also correctly aligning tip 406 with a hole inthe side of the implant for the insertion of the locking pin/screw.Depending on whether there are one or two locking mechanisms 400 presentin the invention will determine the number of slots 219 present inalignment body 214. Although not shown, it would be understood by oneskilled in the art that the locking pin/screw may include externalthreads for engaging the side hole of the implant or the internal lengthadjustment mechanism. An alternative locking mechanism either on thehead or engagement end of the locking pin/screw may be used to securethe locking pin/screw to the internal length adjustment mechanism of theimplant.

As shown in FIG. 4, surgical instrument 10 may use two lockingmechanisms 400. If this is the case, connecting rods 403 will generallyrun parallel to each over the length of surgical instrument 10. Havingtwo locking mechanisms 400 present allows the operating surgeon tosecure the implant at two locations to ensure long term stability of theoverall length of the implant post-operatively.

The surgical technique for implantation of an implant 700 is well knownin the art, including the appropriate surgical exposure and dissectiontechniques. The method generally includes, obtaining an implant 700 andsurgical instrument 10 that may include handle assembly 100 positionedat the proximal end of surgical instrument 10, elongate member 201having a first end 202 being located adjacent to handle assembly 100 andsecond end 203 connected to implant engagement assembly 204. Surgicalinstrument 10 may further have length control mechanism 300, whichgenerally will be constructed of gripping portion 301, gear assembly 302and drive shaft 303. Surgical instrument 10 may yet further have atleast one locking mechanism 400 that has gripping portion 401, couplingend 402 and connecting rod 403. It should be understood that all of theabove noted instrument components and respective elements include thesame structural and functionality characteristics as describedpreviously herein.

The method may further include the step of coupling implant 700 toimplant engagement assembly 204, or more specifically engagement member216. Implant 700 is grasped or held by surgical instrument 10 when theoperating surgeon places implant 700 between engagement members 216. Theoperating surgeon then rotates either clockwise or counter-clockwiseelongate member 201 via holding gripping portion 211 depending onwhether arms 207, 208 need to be spread farther apart or brought closertogether to make contact with implant 700. The operating surgeon mayforego holding onto the gripping portion 211 and may also turn elongatemember 201 along its shaft as well. Upon rotation of elongate member201, external threads 212 engage internal threads 209 of actuation body205 causing actuation body 205, depending on the direction of rotationof elongate member 201, to move either proximally or distally. Movementof actuation body 205 results in drive links 213 actuating arms 207, 208to either move closer together to grasp the implant or farther apart torelease the implant from between engagement members 216. The pivotingconnection between arms 207, 208 and engagement member 216 allowsholding portion 206 to accommodate and engage a wide range of sizes,configurations and diameters of implants.

As shown in FIG. 9, the surgical method may also include the steps ofinserting surgical instrument 10 and the attached implant 700 throughthe skin opening and positioning the attached implant 700 adjacent to aspace 801 between the two target bones 800. For example purposes only,as seen in FIG. 9, the two bones may be vertebral bodies or vertebrae800.

FIGS. 10 and 11 exhibits a possible further step of the method, theextension or contraction of the overall length of implant 700 until thetwo ends 705 (Not Shown) of implant 700 make contact with vertebrae 800resulting in a force being applied by implant 700 to maintain the spaceopening between the two vertebrae 800. The overall length of implant 700may be extended or contracted (shortened) by rotating length controlmechanism 300 either in a clockwise or counter-clockwise direction.Following the engagement of implant 700 with holding portion 206 ofsurgical instrument 10, the operating surgeon will push gripping portion301 in a proximal direction resulting in drive shaft 303 and attachedgear assembly 302 also moving proximally, with gear assembly 302entering hole 702. Although not shown, gear assembly 302 will uponmoving into the inner part of implant 700 engage a correspondinglyconfigured length adjustment mechanism. Once gear assembly 302 isengaged with the length adjustment mechanism, the operating surgeon willturn gripping portion 301 either in a clockwise or counter-clockwisedirection. When gripping portion 301 is rotated, drive shaft 303 andconnected gear assembly 302 will also rotate. As described in theabove-noted pending applications that have been incorporated herein byreference, length adjustment mechanism of implant is configured toconvert the rotational movement of gear assembly 302 into translationalmovement within the implant. Essentially, when length control mechanism300 is rotated in one direction implant 700 will extend or get longerand rotating length control mechanism 300 in the opposition directionwill shorten or contract implant 700 while implant is placed between twobones. This novel functionality provides the operating surgeon with theability to accurately adjust and ensure proper implant sizing withoutcompromising positioning within the operative space.

FIGS. 11 and 12 show further the possible step of fixing or securing theoverall length of implant 700 by the insertion of locking pins/screws405 into holes 704 of implant 700 once the appropriate overall lengthhas been determined. The operating surgeon uses locking mechanism 400 byinitially coupling locking pins 405 to tips 406 (Not Shown). Followingthe final positioning and sizing of the implant in vivo, the operatingsurgeon will hold and turn gripping portion 401 that in turn rotatesconnecting rod 403. Depending on the locking or thread configuration oflocking pin 405 and hole 704, gripping portion 401 may be turned eitherin a clockwise or counter-clockwise direction. Gripping portion 401 isthen pushed in a proximal direction causing locking pin 405 to enterhole 704 and engage either threads or another securement configurationwithin implant 700. Following the rotational insertion of locking pin405 into hole 704, the length adjustment mechanism will be locked inplace, thereby fixing the overall length of implant 700. Once lockingpin 405 is fully seated, the operating surgeon will move lockingmechanism 400 in a distal direction and uncouple tip 406 from lockingpin 405.

It should be understood by those skilled in the art that the surgicalmethod and use of surgical instrument 10 described herein may beperformed using either anterior, posterior or lateral approaches to theexample spinal column. In addition, an operating surgeon may use aminimally invasive surgical approach and employ surgical instrument 10because of the multi-functionality (i.e., grasp, extend/contract andlock) operation of surgical instrument 10 relative to implant 700. It isfurther contemplated that surgical instrument 10 may be sized to allowfor endoscopic insertion. Having these multiple functions incorporatedinto one instrument addresses a long felt need of providing theoperating surgeon with the ability to keep one instrument in the woundand to not have to repetitively remove the instrument and replace itwith a different instrument to perform another function. Having amulti-purpose surgical instrument will lessen the potential for tissuedisruption and adjacent structural damage.

It is further contemplated that a method of fabricating surgicalinstrument 10 may include the steps of providing handle assembly 100with an additional step of providing elongate member 201 with one end202 of the elongate member 201 being positioned adjacent to handleassembly 100 and second end 203 of elongate member 201 being moveably orthreadingly connected to implant engagement assembly 204. Rotationalmovement of elongate member 201 relative to handle assembly 100 andimplant engagement assembly results in the grasping and holding of theimplant between engagement members 216.

The fabrication method may also include the further step of providing alength control mechanism 300 that typically allows the operating surgeonto adjust the overall length of the implant while holding the implant inplace between engagement members 216. Yet a further step of the methodmay include providing at least one locking mechanism 400 for thesurgical instrument 10. Locking mechanism 400 permits the operatingsurgeon with the ability to secure and fix the overall length of theimplant after the final positioning and sizing is accomplished in vivo.

It is further contemplated that a spinal implant insertion kit comprisedof various cross-sectional sizes, cross-sectional polygonal andcircular/oval shapes and longitudinal lengths of implants and acorresponding surgical instrument 10 will be available as a kit. Thiswill allow the operating surgeon to pick and choose these modularcomponents that are necessary to assemble a spinal implant that bestfits into a certain spinal segment or to address a certain anatomicaldeformity presented in a patient. The kit would further include a singleinserter 10 that may be used with the multiple sized (both length anddiameter) spinal implants. It is also contemplated that multiple sizedinserters may be included in the kit to accommodate the various anatomicregions of the spine and the corresponding implant sizes (i.e., lumbar,thoracic and cervical). Inserter 10 includes handle assembly 100,elongate member 201, length control mechanism 300 and at least onelocking mechanism 400. For brevity sake, all of the above noted insertercomponents and respective elements will not be discussed again here andinclude the same structural and functionality characteristics asdescribed previously herein.

Although the preferred embodiments have been depicted and described indetail herein, it will be apparent to those skilled in the relevant artthat various modifications, additions and substitutions can be madewithout departing from its essence and therefore these are to beconsidered to be within the scope of the following claims.

1. A surgical instrument for inserting an implant between two bones, thesurgical instrument comprising: a handle assembly; an elongate memberhaving a first end and a second end, and a longitudinal axis extendingthere between, the elongate member being moveably connected to animplant engagement assembly, the implant engagement assembly being at adistal end of the surgical instrument and being configured to hold theimplant; and a length control mechanism for adjusting the overall lengthof the implant when the implant has been placed between the two bones,the length control mechanism comprising a gripping portion, a gearassembly and a drive shaft positioned intermediate the gripping portionand gear assembly, the drive shaft extending through an opening withinthe handle assembly and oriented substantially parallel to thelongitudinal axis of the elongate member, wherein upon movement of theelongate member relative to the implant engagement assembly, the implantengagement assembly adjusts the implant for insertion between the twobones.
 2. The surgical instrument of claim 1, wherein the implantengagement assembly comprises an actuation body and a holding portion,the actuation body being operatively coupled to the second end of theelongate member, and the holding portion comprising a first arm and asecond arm, the first arm and second arm being operatively coupled tothe actuation body and configured to move and engage the implant uponactuation of the actuation body.
 3. The surgical instrument of claim 2,wherein the first arm further comprises an engagement member and thesecond arm further comprises an engagement member, the engagementmembers being pivotally coupled to a distal position, the first arm andthe second arm and are configured to operatively engage the implant uponactivation of the actuation body.
 4. The surgical instrument of claim 3,wherein the engagement member further comprises a distal surface, thedistal surface having an engagement element disposed thereon, theengagement element being sized and configured to hold the implant inposition after actuation of the actuation body.
 5. The surgicalinstrument of claim 1, wherein the first end of the elongate member isconfigured as a gripping portion and the second end of the elongatemember comprises external threads, the threads being sized andconfigured to threadingly engage the actuation body of the implantengagement assembly.
 6. The surgical instrument of claim 1, wherein theelongate member is a cylindrical body.
 7. The surgical instrument ofclaim 1, wherein the gear assembly is positioned proximate to the distalend of the surgical instrument and is configured to mate with a lengthadjustment mechanism in the implant, wherein when the gear assemblymates with the length adjustment mechanism and is rotated, the overalllength of the implant is changed.
 8. The surgical instrument of claim 1,further comprising a locking mechanism for fixing the overall length theimplant after the implant has been placed between the two bones.
 9. Thesurgical instrument of claim 8, wherein the locking mechanism comprisesa gripping portion proximate to the proximal end of the surgicalinstrument, a coupling end and a connecting rod positioned intermediatethe gripping portion and the coupling end, the connecting rod extendsthrough an opening in the handle assembly and is oriented substantiallyparallel to the longitudinal axis of the elongate member.
 10. Thesurgical instrument of claim 9, wherein the coupling end is configuredto detachably couple a locking pin, the locking pin being sized andconfigured to be inserted into and secure the overall length of theimplant after the implant has been placed between the two bones.
 11. Thesurgical instrument of claim 9, wherein the coupling end is fabricatedfrom a flexible material.
 12. The surgical instrument of claim 8,wherein the locking mechanism is rotatable and moveable in a proximal todistal direction.
 13. The surgical instrument of claim 1, wherein thesurgical instrument further comprises a first locking mechanism and asecond locking mechanism, wherein the first locking mechanism and secondlocking mechanism are substantially parallel to each other and to thelongitudinal axis of the elongate member.
 14. A surgical instrument forinserting a spinal implant between two vertebrae, the surgicalinstrument comprising: a handle assembly; an elongate member having afirst end and a second end, and a longitudinal axis extendingtherebetween, the first end being adjacent to the handle assembly andthe second end being rotationably connected to a spinal implantengagement assembly, the spinal implant engagement assembly being at adistal end of the surgical instrument; a length control mechanism foradjusting the overall length of the spinal implant when the spinalimplant has been placed between two vertebrae, the length controlmechanism comprising a gripping portion, a gear assembly and a driveshaft positioned intermediate the gripping portion and gear assembly,the drive shaft extends through a first opening within the handleassembly and is oriented substantially parallel to the longitudinal axisof the elongate member; and a first locking mechanism for securing theoverall length of the spinal implant after the spinal implant has beenplaced between the two vertebrae, the first locking mechanism comprisesa gripping portion proximate to the proximal end of the surgicalinstrument, a coupling end and a connecting rod positioned intermediatethe gripping portion and the coupling end, the connecting rod extendsthrough a second opening in the handle assembly and is orientedsubstantially parallel to the longitudinal axis of the elongate member.15. The surgical instrument of claim 14, wherein the spinal implantengagement assembly further comprises an actuation body and a holdingportion, the actuation body being operatively coupled to the second endof the elongate member, and the holding portion comprising a first armand a second arm, the first arm and second arm being operatively coupledto the actuation body and configured to move and engage the spinalimplant upon actuation of the actuation body.
 16. The surgicalinstrument of claim 15, wherein the first arm further comprise anengagement member and the second arm further comprises an engagementmember, the engagement members being pivotally coupled to a distalportion of the first arm and the second arm and are configured tooperatively engage the spinal implant upon activation of the actuationbody.
 17. The surgical instrument of claim 16, wherein the engagementmember further comprises a distal surface, the distal surface having anengagement element disposed thereon, the engagement element being sizedand configured to hold the spinal implant in position after actuation ofthe actuation body.
 18. The surgical instrument of claim 14, wherein thefirst end of the elongate member is configured as a gripping portion andthe second end of the elongate member comprises external threads, thethreads being sized and configured to threadingly engage the actuationbody of the spinal implant engagement assembly.
 19. The surgicalinstrument of claim 14, wherein the elongate member is a cylindricalbody.
 20. The surgical instrument of claim 14, wherein the gear assemblyof the length control mechanism is positioned proximate to the distalend of the surgical instrument and is configured to mate with a lengthadjustment mechanism in the spinal implant, wherein when where the gearassembly mates with the length adjustment mechanism and is rotated, theoverall length of the implant is changed.
 21. The surgical instrument ofclaim 14, wherein the coupling end of the first locking mechanism ispositioned proximate the distal end of the surgical instrument and isconfigured to detachably couple a locking pin, the locking pin beingsized and configured to be inserted into and secure the overall lengthof the spinal implant after the spinal implant has been placed betweenthe two vertebrae.
 22. The surgical instrument of claim 14, wherein thesurgical instrument further comprises a second locking mechanism,wherein the second locking mechanism is substantially parallel to thefirst locking mechanism and to the longitudinal axis of the elongatemember.
 23. The surgical instrument of claim 14, wherein the firstlocking mechanism is rotatable and moveable in a proximal to distaldirection.
 24. The surgical instrument of claim 14, wherein the couplingend of the first locking mechanism is fabricated from a flexiblematerial.
 25. A surgical method of inserting an implant between twobones, the method comprising: surgically creating an opening on the skinof a patient, wherein the opening is proximate the location of the twobones; obtaining a surgical instrument comprising: a handle assembly; anelongate member having a first end and a second end, and a longitudinalaxis extending therebetween, the first end being adjacent to the handleassembly and the second end being moveably connected to an implantengagement assembly, the implant engagement assembly being at a distalend of the surgical instrument; a length control mechanism for adjustingthe length of the implant when the implant has been placed between twobones, the length control mechanism comprising a gripping portion, agear assembly and a drive shaft positioned intermediate the grippingportion and gear assembly, the drive shaft extends through a firstopening within the handle assembly and is oriented substantiallyparallel to the longitudinal axis of the elongate member; and at leastone locking mechanism for securing the overall length of the implantafter the implant has been placed between the two bones, the at leastone locking mechanism having a gripping portion proximate to theproximal end of the surgical instrument, a coupling end and a connectingrod positioned intermediate the gripping portion and the coupling end,the connecting rod extending through a second opening in the handleassembly and is oriented substantially parallel to the longitudinal axisof the elongate member, coupling the implant to the implant engagementassembly; inserting the surgical instrument and coupled implant into theopening; positioning the implant into a space between the two bones;extending the implant to an overall length and causing the implant tocontact and apply a force to the two bones to maintain the space betweenthe two bones; and fixing the overall length of the inserted implant.26. The method of claim 25, wherein the extending the implant furthercomprises employing the length control mechanism by mating the gearassembly with a length adjustment mechanism in the implant and changingthe overall length of the implant by rotating the mated gear assembly.27. The method of claim 25, wherein the fixing the overall length of theinserted implant further comprises employing the at least one lockingmechanism and inserting the locking pin into the implant, therebysecuring the overall length of the implant between the two bones.
 28. Amethod of fabricating a surgical instrument for inserting an implantbetween two bones, the method comprising: providing a handle assembly;providing an elongate member having a first end and a second end, and alongitudinal axis extending there between, the first end beingpositioned adjacent handle assembly and the second end being moveablyconnected to an implant engagement assembly, the implant engagementassembly being at a distal end of the surgical instrument; and providinga length control mechanism for adjusting the overall length of theimplant when the implant has been placed between two bones, the lengthcontrol mechanism comprising a gripping portion, a gear assembly and adrive shaft positioned intermediate the gripping portion and gearassembly, the drive shaft extending through a first opening within thehandle assembly and oriented substantially parallel to the longitudinalaxis of the elongate member, wherein upon movement of the elongatemember relative to the handle assembly and implant engagement assembly,the implant engagement assembly couples the implant for insertionbetween the two bones.
 29. The method of claim 28, further comprisingproviding at least one locking mechanism for securing the overall lengthof the implant after the implant has been placed between the two bones,the at least one locking mechanism having a gripping portion proximateto the proximal end of the surgical instrument, a coupling end and aconnecting rod positioned intermediate the gripping portion and thecoupling end, the connecting rod extending through a second opening inthe handle assembly and is oriented substantially parallel to thelongitudinal axis of the elongate member.
 30. The method of claim 29,wherein providing at least one locking mechanism further comprisesfabricating the coupling end from at least one of a flexible metal andpolymer.
 31. A spinal implant insertion kit, the kit comprising: aspinal implant for placement between two vertebrae; and a surgicalinstrument comprising: a handle assembly; an elongate member having afirst end and a second end, and a longitudinal axis extendingtherebetween, the first end being adjacent to the handle assembly andthe second end being moveably connected to a spinal implant engagementassembly, the spinal implant engagement assembly being at a distal endof the surgical instrument; a length control mechanism for adjusting thelength of the spinal implant when the spinal implant has been placedbetween the two vertebrae, the length control mechanism comprising agripping portion, a gear assembly and a drive shaft positionedintermediate the gripping portion and gear assembly, the drive shaftextends through a first opening within the handle assembly and isoriented substantially parallel to the longitudinal axis of the elongatemember; and at least one locking mechanism for securing the overalllength of the spinal implant after the spinal implant has been placedbetween the two bones, the at least one locking mechanism having agripping portion proximate to the proximal end of the surgicalinstrument, a coupling end and a connecting rod positioned intermediatethe gripping portion and the coupling end, the connecting rod extendingthrough a second opening in the handle assembly and is orientedsubstantially parallel to the longitudinal axis of the elongate member.